514 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



who is the origin of the association among the social hymenoptera, 

 as it is always a fertilized female who builds the nest, moreover, 

 among all the solitary hymenoptera, from which the social hymen- 

 optera are descended. 



It is true that it has been sometimes stated that hymenoptera 

 have wintered in numbers under the same shelter, that certain soli- 

 tary wasps have built nests so close to one another that their nests 

 ended in being joined ; it is true that nests of Polistes and of Vespa 

 have been found containing two or more queens, but it was not 

 observed how these nests were originated, and these cases are so 

 rare that we may consider them purely as exceptions. It is true 

 also that H. von Ihering discovered in Brazil that the nests of 

 various social wasps continually contained a certain number of 

 fertilized females, and that K. von Ihering saw that the case was 

 the same for the bumblebees in the same region, but the origin of 

 these nests is unknown to us. To pretend with the authors that the 

 " monogamy " of the social hymenoptera of the temperate regions 

 was derived from the " polygamy " of the social hymenoptera of 

 tropical regions under the influence of the lowering of temperature 

 since Tertiary time, the winter causing the death of the neuters and 

 the dispersion of the fertilized females, is to forget two positive 

 facts : First, that there are monogamous societies of hymenoptera in 

 the tropical regions; the polygamous associations might be derived 

 from them through the fact of the climate, the new fertilized fe- 

 males remaining in the association, which is permanent, with the 

 neuters; second, that in the temperate regions there exist societies 

 of wasps which disperse well before the appearance of the first 

 cold weather, the evolution of their nest building being entirely 

 comparable with that of the solitary hymenoptera from which they 

 sprang. 



We conclude, then, that the present phenomena of the constitution 

 of insect societies are a reproduction of the phenomena which origi- 

 nally gave them birth, and with this view we shall not have too much 

 difficulty in interpreting the facts. 



III. 



We shall take up separately the termites and the social hymenop- 

 tera. Among the most primitive termites, the nest is hollowed out of 

 rotten wood. It is built by the future royal couple, and after the 

 long betrothal necessary to the ripening of their genital glands, the 

 king and queen are both busy feeding the young. These evolve rap- 

 idly into neuters, which are either male or female, and thus is the 

 society constituted. The completely sexed individuals appear much 

 later. 



